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bherm

Speedometer and Cruise MPH drastically different

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Speedometer/Cruise MPH

80/74 mph

50/50 mph

45/45 mph

40/37 mph

 

I've had the vehicle in to two different Ford Dealerships and they have calibrated it twice and recently updated the software with a new SD card.

Can someone please teach my how to read a speedometer?

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On both of my Ford Edges. Using OEM tires the 2008 Orange Crush ran 2mph slower on the ODO than my GPS. On the 2011 Lullubelle she is running 2mph slower on the ODO than the GPS. Using the GPS has never failed as I do not get stopped by the cops for speeding. (well maybe once) LOL

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The OP's issue is the difference between the speedo needle indicated speed vs. the cruise control set speed.

 

In my opinion, the needle is not calibrated correctly. It is definitely not right. Will try to confirm it with my car.

 

Also note that it will not have any relation to the tire size. The difference is in 2 outputs of the cluster itself.

Edited by omar302

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I checked on my 09 MKX using the GPS on my cell phone & my speedometer is about 2-3 mph fast. That's probably typical.

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Not sure how the whole set up works, but I am assuming the actual speed sensor input for the speedometer is an electro-mechanical input and the cruse control setting is an electronic setting. Does this make sense? Essentially I assume nothing more than a calibration issue.

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The cluster is only electronically connected. There are only electric connectors at the back. The speedo needle is only electronically controlled. Hence why both should have the same reading. They are merely 2 output forms for the same input.

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Yes they are OEM tires.. Ford is in the process of looking into the issue.

The digital readout is correct in my opinion because it is the closest to "Speedometer" app on my phone.

 

If Ford cannot resolve the issue they said they might buy it back. Anyone know how that process works?

And for the record I like my EDGE...

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But the speedometer needle itself is mechanical......

The speedometer needle is driven by an electric motor/servo.

 

Edit: Here is a cluster were you can see the back of it.

Edited by omar302

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The speedometer needle is driven by an electric motor/servo.

 

Right - which makes it a mechanical device, not an electronic device. As such a physical change to the needle attachment point or the motor/gears/servo will cause it to read incorrectly.

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Yes, it could be, or the signal driving the servo could be wrong making it an electronic error & not mechanical.

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OK I had to check mine out. Here is what I was seeing. Yes I set it to 77mph ODO was reading 77 as always (gps was at 75/6mph). Keep in mind the setting will never change since it is a goal for the car to match. The speedometer did vary a bit depending on hills (the up and down kind) thus the speedometer was up and down and varied on occasions. In a perfect world they would both match, but one is a setting and the other is real time input so to speak. Thus they will never actually match all the time.

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When I set my cruise the speedometer needle reads the same as what cruise reads but both read one mph faster than gps. Maybe made that way so folks won't speed????

 

Larry

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